cp 0 0 0.0.0.0:21 0.0.0.0:* LISTEN 26848/xinetd means that your proftpd is controlled by xinetd. xinetd provides the ability to start a deamon only when someone calls a specific port. Please check /etc/xinetd.d/ for files which point to an ftp-server (for example "service ftp" in headline.

It might be called just ftpd on your system. You might be able to browse for the service name by scanning the init.d files: ls /etc/rc.d/init.d/ or wherever your system has those.
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CalebApr 13 '11 at 14:40